U.S. patent application number 10/398875 was filed with the patent office on 2004-02-12 for catalyst system for high-cis polybutadiene.
Invention is credited to Le Roy, Patrick, Potlet, Jean-Marc, Sabatier, Alain, van der Huizen, Adriaan A..
Application Number | 20040029722 10/398875 |
Document ID | / |
Family ID | 22903940 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040029722 |
Kind Code |
A1 |
van der Huizen, Adriaan A. ;
et al. |
February 12, 2004 |
Catalyst system for high-cis polybutadiene
Abstract
A catalyst system suitable for use in the production of high cis
polybutadiene is disclosed. The catalyst system includes a cobalt
salt of the formula.sup.CoAx?, where A is a monovalent or divalent
anion and x is 1 or 2; an alkyl aluminum chloride compound of the
structure R.sub.2AlCl, where R is an alkyl group containing 2-8
carbon atoms; a trialkyl aluminum compound of the formula
R.sub.3Al, where R is an alkyl group containing 2-8 carbon atoms;
and a catalytic amount of water.
Inventors: |
van der Huizen, Adriaan A.;
(Castricum, NL) ; Potlet, Jean-Marc; (Veaux,
FR) ; Sabatier, Alain; (Lacon de Provence, FR)
; Le Roy, Patrick; (Salon de Provence, FR) |
Correspondence
Address: |
THE DOW CHEMICAL COMPANY
INTELLECTUAL PROPERTY SECTION
P. O. BOX 1967
MIDLAND
MI
48641-1967
US
|
Family ID: |
22903940 |
Appl. No.: |
10/398875 |
Filed: |
April 11, 2003 |
PCT Filed: |
October 2, 2001 |
PCT NO: |
PCT/US01/30855 |
Current U.S.
Class: |
502/152 ;
502/150; 502/153; 502/154; 526/153; 526/171; 526/335 |
Current CPC
Class: |
C08F 136/06 20130101;
C08F 136/06 20130101; C08F 4/26 20130101; C08F 136/06 20130101;
C08F 4/7096 20130101 |
Class at
Publication: |
502/152 ;
502/150; 502/153; 502/154; 526/335; 526/153; 526/171 |
International
Class: |
B01J 031/00; C08F
004/44 |
Claims
1. A catalyst system suitable for use in the production of high cis
polybutadiene, comprising: a) a cobalt salt of the formula
CoA.sub.x, where A is a monovalent or divalent anion and x is 1 or
2; b) alkyl aluminum chloride compound of the structure R.sub.2AlCl
where R is an alkyl group containing 2-8 carbon atoms; c) trialkyl
aluminum compound of the formula R.sub.3Al, where R is an alkyl
group containing 2-8 carbon atoms; and d) water.
2. The catalyst system of claim 1 wherein the alkyl aluminum
chloride compound is ethylaluminum sesquichloride and the trialkyl
aluminum compound is trioctylaluminum.
3. The catalyst system of claim 2 wherein the cobalt salt is cobalt
neodecanoate.
4. The catalyst system of claim 2 further comprising a ternary
alkyl amine or a ternary aryl amine.
5. The catalyst system of claim 2 wherein the ethylaluminum
sesquichloride; and trioctyl aluminum are reacted together prior to
combining with the other elements.
6. The catalyst system of claim 1 wherein the cobalt salt is
present in an amount such that the ratio of Co to Al is from 1:75
to 1:150.
7. The catalyst system of claim 2 wherein the ethylaluminum
sesquichloride and trioctyl aluminum are present in an amount such
that the concentration of Al is in the range of from 0.002 to 0.004
moles per liter.
8. The catalyst system of claim 1 wherein the water is present in
an amount of 0.1 to 0.8 moles per mole of the alkyl aluminum
chloride compound.
9. The catalyst system of claim 4 wherein the ternary alkyl amine
or ternary aryl amine is triethanolamine or triethylamine.
10. The catalyst system of claim 4 wherein the ternary alkyl amine
or ternary aryl amine present in an amount such that the molar
ratio of Co to N in the system is in the range of from 1:1 to
1:3.
11. A catalyst system suitable for use in the production of high
cis polybutadiene, comprising: a) cobalt neodecanoate; b)
ethylaluminum sesquichloride; c) trioctyl aluminum; and d) water,
wherein ethylaluminum sesquichloride and trioctyl aluminum are
added in such an amount that the concentration of Al is in the
range of from 0.002 to 0.004 moles per liter, and the cobalt salt
is present in an amount such that the molar ratio of Co to Al is in
the range of 1:75 to 1:150.
12. The catalyst system of claim 11 further comprising a ternary
alkyl amine in an amount such that the molar ratio of Co to N in
the system is in the range of from 1:1 to 1:3.
13. A process for producing polybutadiene having a high cis content
comprising contacting a feed comprising 1,3,-butadiene, butene and
cyclohexane with a catalyst system under conditions sufficient to
polymerize the 1,3-butadiene, wherein the catalyst system
comprises: a) a cobalt salt of the formula CoA.sub.x, where A is a
monovalent or divalent anion and x is 1 or 2; b) alkyl aluminum
chloride compound of the structure R.sub.2AlCl where R is an alkyl
group containing 2-8 carbon atoms; c) trialkyl aluminum compound of
the formula R.sub.3Al, where R is an alkyl group containing 2-8
carbon atoms; and d) water.
14. The process of claim 13 wherein the feed additionally contains
benzene.
15. The process of claim 14 wherein the feed comprises 20 percent
by weight 1,3-butadiene and 55 percent by weight butene.
16. The process of claim 15 wherein the catalyst system further
comprises a ternary alkyl amine or a ternary aryl amine.
17. The process of claim 16 wherein the cobalt salt is cobalt
neodecanoate; the alkyl aluminum chloride compound is ethylaluminum
sesquichloride; the trialkyl aluminum compound is trioctyl
aluminum; and wherein ethylaluminum sesquichloride and trioctyl
aluminum are added in such an amount that the concentration of Al
is in the range of from 0.002 to 0.004 moles per liter, and the
cobalt salt is present in an amount such that the molar ratio of Co
to Al is in the range of 1:75 to 1:150, and wherein the ternary
alkyl amine or ternary aryl amine is triethanolamine or
triethylamine added in such amount so that the molar ratio of
cobalt to nitrogen is the range of 1:1 to 1:3.
Description
FIELD OF TE INVENTION
[0001] The present invention relates to an improved catalyst system
for use in the polymerization of conjugated diolefins. More
particularly the present invention relates to the selection of
particular Cobalt salts together with particular alkylaluminum
chloride compounds together with water for use as a catalyst,
particularly suited for the production of high-cis
poly(butadiene).
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] Many catalyst systems and production processes are known for
the production of high cis (that is, greater than about 90%, more
preferably greater than 95% in the cis formation) polybutadienes.
These processes typically involve the polymerization of
1,3-butadiene in an inert liquid polymerization medium in the
presence of a homogeneous catalyst system. The catalyst system
typically comprises a transition metal (principally cobalt) salt
with an alkyl aluminum halide.
[0003] For example, U.S. Pat. No. 3,135,725 teaches a high cis
polybutadiene can be produced by polymerizing 1,3-polybutadiene in
an inert solvent in the presence of a catalyst which contains
cobalt in complex combination with an alkyl aluminum chloride.
[0004] Recently, European Patent 0,652,239 B1 disclosed a process
for producing high-cis polybutadiene comprising polymerizing
1,3-butadiene in an inert hydrocarbon solvent together with water
and a catalyst system comprising (in specified ratios) (1) a
substantially anhydrous divalent cobalt salt CoA.sub.m, where A is
a monovalent or divalent anion of the salt and m is 0 or 1; (2)
diethyl aluminum chloride or ethyl aluminum sesquichloride and (3)
an organo aluminum compound of the formula R.sub.3Al, wherein R is
an alkyl group having from 8-12 carbon atoms (and optionally
triethyl aluminum). The addition of the trialkyl aluminum compounds
was said to reduce the level of gel formation in the reaction
product.
[0005] Currently, cobalt dioctoate is the most commonly used source
of cobalt in the industry. This is also the preferred Cobalt salt
in EP 0,652,239. Similarly, the most commonly used, and EP
0,652,239's preferred organo aluminum chloride species is diethyl
aluminum chloride ("DEAC"). This is probably due in part to cobalt
dioctoate's relatively high solubility in DEAC. It has been
observed, however, that DEAC promotes branching in the
polybutadiene which leads to the formation of gels, causing fouling
on the reactor surfaces. Increased fouling requires the reactors to
be shut down for maintenance more frequently.
[0006] Accordingly, it is an objective of the present invention to
provide a catalyst system which reduces branching and fouling
without a substantial decrease in the catalyst activity.
[0007] It has been discovered that the use of ethyl aluminum
sesquichloride together with trioctyl aluminum produces a more
linear product and exhibits less fouling that when DEAC alone is
used. This effect is somewhat offset by slower conversion rates
which were observed. These conversion rates were improved however,
by using cobalt neodecanoate as the cobalt salt. Furthermore it was
observed that the activity of all of these cobalt systems could be
improved by the addition of an amount of ternary alkyl or aryl
amines. Thus it was possible to achieve similar conversion rates,
while simultaneously reducing branching and reducing fouling of the
reactor.
[0008] Accordingly, one aspect of the invention is the use of
ethylaluminum sesquichloride and trioctylaluminum as co-catalyst
with a cobalt salt. Another aspect of the present invention is the
use of cobalt neodecanoate as the cobalt salt. Yet another aspect
of the present invention relates to the use of ternary alkyl amines
or ternary aryl amines as an additive to a catalyst system which
comprises a cobalt salt together with an organo aluminum
halide.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The present invention broadly relates to a catalyst system
suitable for use in the production of high cis polybutadiene. The
catalyst system comprises a cobalt salt of the formula CoA.sub.x,
wherein A is a monovalent or divalent anion and x is 1 or 2; and an
alkyl aluminum chloride compound of structure R.sub.2AlCl where R
is an alkyl group containing 2-8 carbon atoms; and water. The
catalyst system may optionally further comprise a ternary alkyl
amine or a ternary aryl amine and/or a trialkyl aluminum compound
of the formula R.sub.3Al where R is as defined above.
[0010] The cobalt salt of the present invention can be any of those
generally known in the art. Examples include cobalt (ii)
acetylacetonate, cobalt (II) octoate, cobalt (II) isooctoate,
cobalt (II) naphthanate, Cobalt (II) neodecanoate and their cobalt
(III) congeners. In general it is preferred that the cobalt salt be
anhydrous. Of these, cobalt (II) neodecanoate was observed to give
the most activity when using the preferred ethylaluminum
sesquichloride/trioctyl aluminum co-catalyst.
[0011] The catalyst system of the present invention also includes
an alkyl aluminum chloride compound of structure R.sub.2AlCl where
R is an alkyl group containing 2-8 carbon atoms. The R group may be
straight or branched. Suitable compounds include diethylaluminum
chloride, di-n-butylaluminimum chloride, di-n-octylaluminum
chloride, ethyl-n-octylaluminum chloride, ethyl aluminum
dichloride, and ethylaluminum sesquichloride. It is preferred that
a trialkyl aluminum compound of formula R.sub.3Al, where R is as
defined above, also be part of the catalyst system. Suitable
trialkyl aluminum compounds include triethylaluminum, and trioctyl
aluminum. It should be understood that the trialkylaluminum can
first reacted with the alkylaluminum chloride compound to form an
intermediate species before combining with the catalyst system. For
example, an equimolar mixture of ethyl aluminum sesquichloride
together with trioctyl aluminum (which mixture may hereafter be
referred to as "EOAC") was shown to give particularly good results
in terms of maintaining activity while reducing fouling and
branching, when added to the catalyst system.
[0012] The catalyst system also contains a catalytic amount of
water. The amount of water should typically be in the range of 0.1
to 0.8 moles per mole of the alkyl aluminum chloride compound used,
with about 0.5 being most preferred. The exclusion of additional
moisture can be achieved my maintaining a nitrogen or other inert
atmosphere over the liquid when preparing the reaction mixture and
carrying out the polymerization.
[0013] It has been discovered that the presence of a ternary amine
can also boost the performance of the catalyst system. The catalyst
system can therefore optionally contain a ternary alkyl/aryl amine.
The alkyl groups which may be used in this aspect of the invention
may be linear or have branching. Aryl groups can similarly be
chosen from all existing materials. It is generally preferred, that
the amine be somewhat water soluble, however, as this allows it to
me more easily removed in water washes. Thus shorter chain lengths,
such as C6 or less, are generally preferred. It should be
understood that the same amine may have alkyl and aryl
characteristics. Suitable examples include triethylamine,
tributylamine, triphenylamine, dimethylphenylamine, and
triethanolamine, with triethylamine and triethanolamine being
generally more preferred. The amine should be added in an amount
such that the molar ratio of cobalt to nitrogen is in the range of
1:0.1 to 1:10, more preferably in the range of 1:1 to 1:3.
[0014] As is generally known in the art, the catalyst system of the
present invention will be added to a mixture comprising
1,3-butadiene in one or more hydrocarbon materials which act as a
solvent at least for the monomer. The solvent can also be useful to
control the polymerization temperature by refluxing. In this
regard, it should be appreciated that by mixing two or more
solvents the desired polymerization temperature can be more
precisely achieved. Preferred solvents include aliphatic,
cycloaliphatic, aromatic, and monoolefmic hydrocarbons and mixtures
thereof. Particularly well suited solvents for use with the
catalyst system of the present invention include C.sub.4-C.sub.8
aliphatic hydrocarbons, C.sub.5 to C.sub.10 cyclic aliphatic
hydrocarbons, C.sub.6 to C.sub.9 aromatic hydrocarbons, and C.sub.4
to C.sub.6 monoolefmic hydrocarbons or mixtures thereof. 2-butene,
1-butene, cyclohexane, benzene, pentane, hexane, heptane, toluene,
and xylene are specific examples of such suitable solvents.
[0015] The catalyst should be made up of the various components in
ratios such that when added to the solvent and monomer, the cobalt
is present in the reaction medium in a ratio of cobalt to Al from
approximately 1:75 to 1:150, with a range of 1:90 to 1:125 being
more preferred. Typical cobalt concentrations in the reaction
medium are about 2 ppm, although they can range from 0.2 to 10 ppm.
The alkyl aluminum chloride/trialkyl aluminum compounds are added
such that the total amount of Al in the reaction system is in the
range of 0.002-0.004 molar. It is preferred that the concentration
of Al in the final reaction mixture be approximately 0.003 molar.
It is preferred that from 10 to 90, more preferably 50 to 75
percent of the total Al come from the alkyl aluminum chloride
species.
[0016] In conducting the polymerization using this catalyst, many
procedures may be filed. This catalyst system appears to be
particularly effective in polymerizing 1,3-butadiene in a feed
comprising about 5 to 30 percent, more preferably 15 to 25, most
preferably about 20 percent by weight 1,3-butadiene, 30 to 70, more
preferably 45 to 65 and most preferably about 55 percent butenes (1
butene and/or 2-butene), and 20 to 40, more preferably 25 to 35 and
most preferably about 25 to 30 percent by weight cyclohexane,
optionally with benzene. A preferred cyclohexane/benzene mix was
such that the ratio of cyclohexane to benzene was about 0.65.
[0017] Normally the polymerization is conducted at a temperature in
the range of -35.degree. to 100.degree. C., more preferably from
-10.degree. C. to 50.degree. C., most preferably 0.degree. C. to
40.degree. C. The polymerization can be conducted in a pressure
autoclave if desired.
[0018] The polymerization can be advantageously carried out in the
following manner: The butadiene feed, water and a mixture of the
alkyl aluminum chloride compound with the trialkyl aluminum
compound, can be added to the reaction vessel in any order, and can
be mixed together in the reaction vessel or before addition to the
reaction vessel. The cobalt catalyst can then be added, optionally
predissolved in a suitable solvent or solvent mixture, and the
polymerization carried out.
[0019] The following examples are presented to further illustrate
the invention, however they are not intended to limit the scope of
the invention to these particular embodiments.
EXAMPLES 1-7
[0020] The following polymerization reactions were carried out in a
5 liter stainless steel stirred reactor equipped with the necessary
auxiliaries, like inlets and outlets for nitrogen, solvents, and
catalysts, a cooling circuit and a premixing vessel. In each case
the reactor was charged with 3 liters of a dry feed consisting of
20 percent by weight 1,3-butadiene, 55 percent by weight butenes
(ratio of butene-2/butene-1 was about 0.3), and 25 percent by
weight cyclohexane/benzene (ratio of cyclohexane to benzene was
about 0.65). At 25.degree. C., a previously prepared mixture of
aluminumalkyl (10 percent by weigh aluminum alkyl in cyclohexane)
with water was added to the feed so as to obtain a 0.00332 molar
solution of Al in the reactor. The water to aluminum ratio was
approximately 0.5. The polymerization was then initiated by
injection of a cobalt solution (10% by weight cobalt salt in
mineral oil) into the reactor so as to obtain a cobalt
concentration of 1.9 ppm. When an amine was present it was added
together with the cobalt solution, in the amounts listed in Table
I. All materials were handled in a dry nitrogen atmosphere. The
solvents and 1, 3-butadiene were dried over alumina columns prior
to use.
[0021] The conversion of the 1,3-butadiene to polybutadiene was
monitored by GC analysis. At approximately 75% conversion, the
polymerization was terminated by the addition of 2 ml ethanol to
the reactor. The polymer solution was then washed with water and
coagulated after addition of a standard hindered phenol antioxidant
polymer stabilizer. The conversion times are reported in Table
I.
[0022] The recovered product was then subjected to the following
analytical tests. Molecular weight determinations (both Mw and Mn)
were carried out with Gel Permeation Chromatography using a Waters
GPC system being maintained at an internal temperature of about
30.degree. C., and employing 5 "mixed bed" Styragel.TM. columns
(HT6, HT5, HT4, HR3, HR1) in a series, a differential refractive
index (DRI) detector and tetrahydrofuran as the eluent at a flow
rate of 0.8 ml/min.
[0023] Viscosities of products at five percent by weight in styrene
solvent (VS) were determined by conventional viscometric
techniques. Mooney viscosities (VM) were determined according to
ASTM 1646, ML 1+4 at 100.degree. C. The ratio VSJVM was used as an
indication of polymer linearity. These results are shown in Table
II
1TABLE I Amine Exam- Concentration Conversion Conversion ple R2A1C1
Cobalt Salt Amine (ppm on feed) 25% (mm) 75% (mm) 1 DEAC Cobalt
octoate -- -- 7.5 32 2 EOAC Cobalt octoate -- -- 10 47 3 EOAC
Cobalt octoate Triethanolamine 0.8 8 40 4 EOAC Cobalt octoate
Triethylamine 0.8 8 37 5 EOAC Cobalt -- -- 7.5 37 neodecanoate 6
EOAC Cobalt Triethanolamine 0.4 7 40 neodecanoate 7 EOAC Cobalt
Triethanolamine 0.8 6 41 neodecanoate
[0024]
2TABLE II Example Mw.sup.a Mn.sup.a Mw/Mn VS (cPs) VM VS/VM 1 374
107 3.5 90 48 1.88 2 395 133 3.0 119 51 2.33 3 399 117 3.4 130 51
2.55 4 369 106 3.5 113 49 2.31 5 364 98 3.7 96 45 2.13 6 353 92 3.8
87 42 2.07 7 337 99 3.4 73 38 1.92
[0025] As can be seen from the tables, comparative example 1 showed
more branching (VS/VM closer to one) than the other examples. It
can also be observed that the presence of the amine does seem to
have an affect on the reaction rate.
[0026] It should be realized by those skilled in the art that the
invention is not limited to the exact configuration or methods
illustrated above, but that various changes and modifications may
be made without departing from the spirit and scope of the
invention as described within the following claims:
* * * * *